For the purpose of interrupting ultraviolet ray of sunrays harmful to the human body and ultraviolet rays generated from fluorescent lamps which cause luring flying insects, paints containing ultraviolet absorbers and fluorescent lamps provided with heat-shrinkable films are on the market and are also suggested in JP-A-8-111208, JP-A-10-21714 and JP-A-11-106666(the term “JP-A” as used herein means an “unexamined published Japanese patent application”). However, absorption edge of those ultraviolet absorbers is shorter than 380 nm for the purpose of suppressing a yellow tint, or they are capable of absorbing ultraviolet rays to a long wavelength of 410 nm but accompanied by a strong yellow tint, or dyes and pigments are added for adjusting the tone of color for suppressing a tint of yellow. That absorption edge is short means UV-cutting off performance is low, and in particular, three-wavelength type fluorescent lamps, which are expected to spread prevailingly, have not absorption at 380 nm or less, or little if any. Accordingly, since the performance of preventing flying insects of three-wavelength fluorescent lamps themselves is expected, there is no necessity for such contrivances. However, since there remains emission in the vicinity of 405 nm even with three-wavelength type fluorescent lamps, as is apparent from the phototaxis curve of insects (insects generally strongly react to the wavelengths near the ultraviolet region, and this wavelength dependence is graphed) as disclosed in JP-A-7-3189, it is necessary to interrupt the emission line in the vicinity of 405 nm for the purpose of effectively preventing flying insects, therefore it is desired to cut off the rays to 410 nm. The interruption of the rays to 410 nm is accompanied by a tint of yellow. A tint of yellow can be suppressed by the addition of dyes and pigments but this countermeasure results in the sacrifice of transmittance in the visible ray region.
Further, white lamination polyester films mixed with a fluorescent brightening agent as well as an ultraviolet absorber for the purpose of suppressing the yellowing degree due to ultraviolet irradiation which are excellent in light fastness, whitening property and adhesive property are suggested (JP-A-11-291432 and JP-A-11-26821), but the same drawbacks as above still remain unsolved.
Further, as an ultraviolet-cutting off cover for a fluorescent lamp, composition comprising a transparent resin containing a fluorescent brightening agent is suggested (JP-B-6-3682, (the term “JP-B”as used herein means an “examined Japanese patent publication”)), but there is a problem in this technique that the fluorescent brightening agent is deteriorated and causes yellowing.